iPhone sounds terrible on mine. Had the 1st gen and 2 different 3Gs. Used a friends phone and quality was impeccable. I feel its the phone bluetooth. I also own the Bang & Olufsen bluetooth for the iPhone which cost $350. I can hear everyone crystal clear. On the iPhone, people cant hear me worth a damn. I feel its the iPhone itself. Ive had 4 different iPhones and the b-tooth has SUCKED on every single one of them.